[Scott]

I think that in no way did Grima see the full scope of what he had done until it was too late. He was just a love-struck ugly geek who wanted the upper hand in life for once.

Notice what happened at the end of the Scouring of the Shire. We find that Grima is as sickened by Saruman as everybody else and turns on him.

Also notice the scene in The Two Towers where Grima inquires about the army Saruman has the camers pans out to show the legions of Isengard. If you look closely, you can see a tear falling from Grima's eye and the fear creeping into his heart. His expressions read, "Oh my God. What have I done?" like a picture book. Of course this is just the director's and actor's interpretations of Grima, but they've been pretty accurate thus far.

~Scott